''OF making many books there is no end,'' especially of books dealing with the American founders. Every month or so, it seems, we have a new book on one or another of that galaxy of men who over 200 years ago created the United States. No other major nation celebrates its founders as we do, especially founders who existed two centuries ago. We Americans seem to need these authentic historical figures in the here and now; we want to rip our founders out of their historical context, tear them out of their time and place, in order to make them part of our present-day circumstances. Washington, Jefferson, Franklin and the other founders become standards or touchstones by which we measure ourselves. We ask what would they think of our current problems and what would they do to solve them.

In ''Inventing a Nation,'' the inimitable Gore Vidal has his own peculiar explanation for why we Americans have ''so many academic histories of our republic and its origins.'' We want to ''gaze fixedly on the sunny aspects of a history growing ever darker.'' That's why, he says, we have ignored Benjamin Franklin's dire warning in 1787 that our Republic was likely to become corrupted and end in despotism. Instead of realizing that Franklin was correct in his prediction and that we have already arrived at this awful moment of corruption and tyranny, we celebrate Franklin as ''the jolly fat ventriloquist of common lore, with his simple maxims for simple folk.'' So much for all those recent best-selling biographies.

It is hard to know what to make of Vidal, America's super-satirist. Can he be serious? Yes, sometimes. Probably no American writer since Franklin has derided, ridiculed and mocked Americans more skillfully and more often than Vidal. In this latest effort, which is not one of his lively novels about moments in America's past but his attempt to explain where these great founders came from, Vidal has his usual sardonic fun with the creation of the nation, interspersing his history with some witty remarks about our present dreadful circumstances. Sometimes his foray into history writing contains some shrewd judgments, as, for example, in his descriptions of Jefferson's habits and inconsistencies or of John Adams as the representative of the tortured conscience of the nation. But other times, Vidal's history reads as if it had been written by Dave Barry. Take, for example, his description of Adams's reluctance to get any false teeth ''for fear of looking as grim as Washington'': consequently, ''he ate with difficulty, and spoke with the pronounced lisp of the dentally challenged, to use a 21st-century locution.'' Perhaps the best we can say of Vidal with this book is what Franklin famously said of Adams: ''He means well for his country, is always an honest man, often a wise one, but sometimes and in some things absolutely out of his senses.''

At one point Vidal mentions that slavery is still of central concern to us today. But he doesn't capture the half of it. Not only does the overwhelming presence of slavery in early America cast a dark shadow over the sunny aspects of the founding, but it is also driving a huge rethinking of our history. Previous historians of early America, of course, never entirely ignored slavery (how could they?), but they did not bring its harsh brutality and its influence front and center in the way recent historians have. In 1776, one-fifth of America's population was enslaved, and the institution implicated nearly everyone, Northerners as well as Southerners. Four of the five first presidents were slaveholders, including Washington and Jefferson, the principal subjects of these five books. The new United States was not just a republic, it was a slaveholding republic.

If anything can take founders like Washington and Jefferson out of our present and place them back into the particular context of their time, it is this fact that they were slaveholders. Slavery is virtually inconceivable to us. We can scarcely imagine one person owning another for life. Seeing Washington and Jefferson as slaveholders, men who bought, sold and flogged slaves, has to change our conception of them. They don't belong to us today; they belong to the 18th century, to that coarse and brutal world that is so remote from our own.

In writing ''An Imperfect God,'' his honest and compelling study of Washington and slavery, Henry Wiencek came to appreciate only too well that the symbolic significance we attribute to the founders could not survive 18th-century realities. ''Slavery,'' he says, ''wrecks the simple heroic narrative of the Founding.'' Slavery, in Wiencek's superb telling, certainly makes Washington more of a traditional Southern planter than we have usually been willing to admit. Washington was not a cruel man, but relying as he did on slave labor made him act in a manner that to us can only seem cruel. To make his farm pay he worked his slaves hard, divided their families for efficiency, punished them by whipping or selling them and clothed and housed them as meagerly as possible. He, along with other planters, raffled off the slaves, including children, of bankrupt slaveholders who owed him money. He even had some of his slaves' teeth transplanted into his own mouth, though he did pay his slaves for the teeth. Wiencek,+a+historian+and the author, most+recently,+of+The+Hairstons: An American Family in Black and White,'' based this appalling picture of Washington and slavery not only on his own research but also on conversations with the staffs of Mount Vernon and Colonial Williamsburg and with the heirs of slaves. He tells stories of miscegenation and incest in the Washington household that rival anything William Faulkner imagined, though he discounts the story that Washington fathered a mulatto child.